<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<style type="text/css">
			.father{
				height: 160px;
				width: 160px;
				border: 1px solid #B000B0;
				opacity: 0.5;				/*元素及其内容都变透明*/
			}
			.son{
				height: 30px;
				width: 30px;
				background: #87CEEB;
			}
			.father:hover .son{
				display: none;
			}
		</style>
	</head>
	<body>
		<div class="father">
			<div class="son">
				???????????
			</div>
		</div>
	</body>
</html>
